The relation of body weight to length of stay and charges for hospital services for patients undergoing elective surgery: a study of two procedures.

We studied the relation of body weight to lengths of stay and total charges for all patients hospitalized at the Brigham and Women's Hospital for total knee replacement and total hip replacement during a 12-month period. Patients with moderate obesity (actual body weight 141-170 per cent of ideal) had lengths of stay and total charges similar to normal weight patients (body weight 100-110 per cent ideal). However, patients who were extremely overweight (body weight greater than or equal to 188 per cent ideal) had mean lengths of stay 35 per cent longer (28.9 days vs 21.5) and total charges 30 per cent higher ($25,692 vs $19,576) than patients with normal weight. Those who were extremely underweight (body weight less than or equal to 75 per cent ideal) had mean lengths of stay 40 per cent longer (30.1 days vs 21.5) and total charges 35 per cent higher ($26,447 vs $19,576).